I am running CS5 on a Win7 64-bit PC. I have an internal 1TB hard drive with nothing but folders containing my raw images and the various processed versions of them. I use an identical drive to back them up. My backup software is Acronis Home version, and because I don't want the usual compressed backup files, I use Acronis to clone my data drive, every couple of days.
Not wanting to put the drives through such extensive use so often, what I would like to do is mark the files on the data drive as "backed up", and then copy only the newer files to the backup drive after each photo processing session. Years back it was simple to change the attributes of files, but I can't find any way to do this in Win7. The problem is compounded by the fact that even though my folders are arranged chronologically, I often process one or more images in older folders, and sometimes save them in other folders.
Is there any simple way to do such incremental copying of files for backup purposes without having to buy another backup program? And please don't suggest Lightroom, as I have found because of the way I use my files, it further complicates my workflow.
A few points not mentioned.
Hard drives are meant to be used, I have cheap consumer HDDs running (as in transferring data, not just idling or on standby) 24/7 literally for years. Hard drives also fail, that's why you should always have multiple backups. Minimum is one local on-site and one off-site. Only one backup is not really useful. What happens if you have a fire, water damage, or your computer gets stolen?
I'm not sure how Synctoy backs up, but dozens of incremental backups can be a nightmare to recover - you might have to recover each and every single backup, starting from the first one and going one-by-one to the last one. You should occasionally verify the backups against the original files in case of bad sectors or copying errors, or start a new rolling backup every week/month.
FWIW here my backup setup